• Korean Journal of Environmental Biology
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• v.36 no.2
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• pp.131-139
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• 2018

The warming of water as a result of climate change affects fish habitat. Variations in water temperature affect fish physiology almost totally. The rise in water temperature due to climate change leads to hypoxia following decreased oxygen solubility and decreased binding capacity of oxygen-carrying hemoglobin. This study was conducted to evaluate the health status of Atlantic salmon (Salmo salar) fry at elevated water temperatures($20^{\circ}C$) compared with optimum water temperature ($15^{\circ}C$). The method facilitated the detection of biomarker genes using NGS RNAseq analysis and evaluation of their expression pattern using RT-qPCR analysis. The biomarker genes included interferon alpha-inducible protein 27-like protein 2A transcript variant X3, protein L-Myc-1b-like, placenta growth factor-like transcript variant X1, fibroblast growth factor receptor-like 1 transcript variant X1, transferrin, intelectin, thioredoxin-like, c-type lectin lectoxin-Thr1-like, ladderlectin-like and calponin-1. The selected biomarker genes were sensitive to changes in water temperature based on NGS RNAseq analysis. The expression patterns of these genes based on RT-qPCR were similar to those of NGS RNAseq analysis.

• Journal of Environmental Science International
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• v.23 no.10
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• pp.1703-1718
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• 2014

An eco-friendly integrated multi-trophic aquaculture (IMTA) farming technique was developed with the goal of resolving eutrophication by excess feed and feces as fish-farming by-products. A variety of seaweed species were tried to remove inorganic nutrients produced by fish farming. However, there have been few trials to use Sargassum fulvellum in an IMTA system, a species with a relatively wide distribution across regions with various habitat conditions, great nutrient removal efficiency and importance for human food source and industrial purposes. In this regard, our study tried to examine feasibility of using S. fulvellum in an IMTA system by analyzing growth characteristics of the species in an IMTA system comprising of rockfish (Sebastes shlegeli), sea cucumber (Stichopus japonocus) and the tried S. fulvellum (October 2011 - November 2012). We also monitored environment conditions around the system including current speed, water temperature and inorganic nutrient level as they may affect growth of S. fulvellum. S. fulvellum in the IMTA system, which were $15.72{\pm}5.67mm$ long at the start of the experiment in October 2011, grew to a maximum of $1093{\pm}271.13mm$ by May 2012. In September, seaweed growth was reduced to a minimum of $280{\pm}70.43mm$ in length. Then, S. fulvellum began to grow again reaching $325{\pm}196.19mm$ by November 2012. Wet weight of the seaweed was $4.01{\pm}1.89g$ at the start of the experiment and reached a maximum of $109.26{\pm}34.23g$ in May. The weight gradually declined to a low of $15.12{\pm}8.40g$ in September 2012. Weight began to increase once more, rising to $39.27{\pm}21.69g$ by November. During the experiment, the average velocity at the surface and the bottom was 6.5 cm/s and 3.4 cm/s, respectively. The water temperature ranged $5.0-23.5^{\circ}C$, which was considered suitable for growing S. fulvellum. Results of the study indicated no significant differences in inorganic nutrients between pre- and post-IMTA installation. It was thus concluded that S. fulvellum can be a suitable seaweed species to be used in an IMTA system.

• Korean Journal of Ichthyology
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• v.21 no.2
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• pp.76-80
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• 2009

Genetic diversity and genetic structure within the Geum River and Mankyung River populations of the Korean endangered Black shinner (Pseudopungtungia nigra) were assessed by amplified fragment length polymorphism (AFLP). AFLP analysis using five primer combinations generated 447 AFLP bands with 64.1% polymorphism (Geum River 74.6% and Mankyung River 53.6%). The heterozygosities within the two populations were calculated to be 0.170 and 0.104, respectively. Their average genetic diversities are 0.240 and 0.147, respectively. The pairwise Fst value (0.150) indicated distinct genetic differentiation between the two populations. A UPGMA dendrogram based on genetic distance among the individuals revealed a division corresponding to geographical regions, with low genetic variation within the Mankyung River population, and low genetic distance (0.026) between the two populations. Consequently, the two populations may have the same genetic origin The Geum River population will be more suitable than the Mankyung River population for conservation plans to increase the population sizes. Genetic and habitat management will be necessary for the Mankyung River population.

• Journal of Fisheries and Marine Sciences Education
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• v.29 no.2
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• pp.453-465
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• 2017

UN adopted the 2030 Agenda for Sustainable Development and the Sustainable Development Goals (SDGs) in 2015, a set of 17 objectives with 169 targets expected to guide actions over the next 15 years (2016-2030). One goal expressly focuses on the oceans, that is, SDG 14 'Conserve and sustainably use the oceans, seas and marine resources for sustainable development'. More than 30% of fish stocks worldwide were classified by FAO(2016) as overfished. Globally, world capture fisheries are near the ocean's productive capacity with catches on the order of 80 million metric tons. Aquaculture production is increasing rapidly and is expected to continue to increase, but aquaculture encounters some environmental challenges, including potential pollution, competition with wild fishery resources, potential contamination of gene pools, disease problems, and loss of habitat. Accordingly, there have been a variety of world organization and conferences stressing the importance of the implementation of the ecosystem-based fisheries management(EBFM) to overcome these problems. Annual catch of Korean fisheries have shown continuously declining patterns since late 1990s. Most fish stocks are currently known to be over-exploited, and some stocks are depleted due to the increase in fishing intensity and over-capitalization of fishing fleets. Other reasons for the depletion are land reclamations and coastal pollution, which destroy spawning and nursery grounds along the coastal regions. Aquaculture production is also increasing rapidly in Korea. However, several important issues such as gene pool and interaction with capture fisheries should be considered. The EBFM approach should use the best available information coupled with a reasonable application of the precautionary approach. The EBFM has global relevance, and so the real challenge will be to develop and use reliable, robust and cost-effective means of assessing and monitoring the status of ecosystems and their resources, and rapid means of detecting any undesirable and excessive impacts that threaten sustainable use. Future fisheries education should take into account UN's SDGs, which were adopted to achieve the global 2030 agenda. However, there are some difficulties in the current fisheries education system in Korea. First, the current education organizations are limited within the old frame of traditional fisheries sciences. Second, the fisheries education is currently lack of the future-oriented education system and of customized schools or departments. Third, the on-going fisheries education has been based upon few educational policies which are sufficiently relevant to holistic SDGs of the global standard. Accordingly, directions to modern fisheries education for achieving SDGs would be, first, the transition of fisheries education structure into the future-oriented and customized education system. Second, fisheries education needs to shift to the new paradigm, which combines traditional fisheries science education with related fields such as oceanography and environmental sciences to adopt the concept of EBFM. Lastly, fisheries education should accompany relevant policies for effectively achieving SDGs.

• Korean Journal of Ichthyology
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• v.31 no.3
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• pp.123-130
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• 2019

The olfactory organ of the Korean endemic fish, Rhodeus uyekii, a mussel-spawning species, was researched anatomically, histologically and histochemically, for looking into a relation to the physical and chemical condition of its habitat and ecological habit, using stereo microscopy, light microscopy and scanning electron microscopy. The external structure of the olfactory organ consists of the semicircular-shaped anterior nostril with arched shape at its forward position, posterior nostrils and the nasal flap. Within the olfactory chamber, it has the rosette structure with 14 to 15 lamellae which is largely divided into the sensory and non-sensory regions. The sensory region has the olfactory receptor neurons, the supporting cells, the basal cells, the lymphatic cells, and the plasma cells, while the non-sensory region has the stratified epithelial cells, the mucous cells with sulfomucin and 1 type of unidentified cell. In particular, the arched feature in the anterior nostril and the mucous cell of sulfomucin were unique.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.55 no.2
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• pp.121-128
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• 2019

Various artificial reefs provide the fish habitat and nursery, and contribute the improvement of fisheries productivity. The evaluation methods of fishery resources in the artificial reefs have been done by fishing, scuba diving, underwater camera, and scientific echo sounder/sonar. There are a number of studies using echosounders on the quantitative and qualitative evaluations of artificial reefs in various seas around the world. This study focused on the spatial distribution of fishes around artificial reefs and the influential area of reefs off Bukchon, Jeju Island. Not only acoustic data but also various properties of artificial reefs were used in the geographic information system to extract relevant results. As a result, the major material of reefs on this study site was concrete and the number of reefs with that material was the most. The volume of reefs consisted of steel only and steel with riprap was considerably large compared to other reefs. The average NASC in the vertical distribution of fishes in artificial reefs was $31.6m^2/nm^2$ in April, and that was $61.3m^2/nm^2$ in June. The distance between the fish school and their nearest reef in June morning had a wide range from 750 to 3250 m. On the basis of the influence ray of artificial reefs, it had a tendancy of NASC to decrease with distance from the reef in the June morning. It is a preliminary study to present the geospatial analysis example to understand a better way of comprehensive artificial reef environments.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.714-720
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• 2022

A dietary comparison of yellow goosefish Lophius litulon in the South Sea and Yellow Sea was performed by analyzing stomach contents. Using a bottom trawl net from fisheries resources survey vessels of the National Institute of Fisheries Science, 326 individuals were collected from the South Sea and 166 individuals were collected from the Yellow Sea. The total length range of L. litulon was 5.3-68.4 cm for individuals collected from the South Sea and 7.5-55.1 cm for individuals collected from the Yellow Sea. Based on the index of relative importance and the variation in stomach contents by fish size, L. litulon was found to be a piscevore and a spatiotemporally opportunistic feeder fish that fed mainly on pisces. There were differences in the composition of the stomach contents by season, location, and the interaction between the season and the location. Thus, the diet of L. litulon is affected by the prey abundance and prey spectrum of the habitat.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.19 no.2
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• pp.95-107
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• 2016

The gold-spotted pond frog(Pelophylax chosenicus) classified as an Anura in Amphibia is sharply decreasing due to various changes of habitats environment, and designated as IUCN Red List Threatened species(VU; Vulnerable) internationally and domestic endangered species Class-II; therefore, it's in urgent need of the research on habitats restoration of the gold-spotted pond frog in order to prevent its extinction. This study was carried out to verify the effect after restoration by introducing the inhabitation elements deducted by the literature research and a field survey on the habitats for the gold-spotted pond frog in danger of regional extinction in the urban area of Ansan city, Gyeonggi-do, Korea. Accordingly, the capacity for bio-species was increased by expanding the area of habitats into $11,845m^2$, and securing the place for hibernation and corridors and discharge within the habitats, etc. As a result of the monitoring the number of individuals increased by 9.5 times as the reproductive success rate of the gold-spotted pond frog got higher, and by virtue of improvement in the habitats, biodiversity increased to 183 species(4 species of amphibians and reptiles, 4 species of mammals, 17 species of birds, 53 species of insects(terrestrial/Benthic), 4 species of fish, and 102 species of plants). It might be possible to verify the restoration effect of the habitats through continuous monitoring, and suggest the restoration model on the habitats for continuously survivable the gold-spotted pond frog in the urban area by deducting the matters to be improved.

• International Journal of Industrial Entomology and Biomaterials
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• v.33 no.2
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• pp.92-95
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• 2016

The black soldier fly is economically important because its prepupae are used as feed for many animals, including fish and swine. In Korea, black-soldier-fly farms have attempted to increase annual breeding and mass egg production for use in animal feed, as well as the decomposition of organic waste. Such efforts require an understanding of optimal mating and oviposition techniques. Specifically, adult densities and cage size may both improve the efficiency of mass egg production. Our study used four sizes of nylon cages ($1.0{\times}1.0{\times}2.5m$, $1.5{\times}1.5{\times}2.5m$, $2.0{\times}2.0{\times}2.5m$, $2.5{\times}2.5{\times}2.5m$) and three density treatments (4 kg, 8 kg, and 10 kg of pupae) to investigate optimal habitat size and adult density. We found that cage size (independent of density) did not significantly influence female fecundity (number of egg clutches and egg weight), whereas higher densities increased egg number and weight regardless of cage size. Thus, we recommend manipulating adult density to enhance productivity in commercial black-soldier-fly farming. However, we also propose further detailed research to develop methods that account for seasonal changes and environmental conditions, as climatic variables (temperature, sunlight) likely influence female fecundity as well.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.1
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• pp.155-165
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• 2014

In this study, using a complex of physical, chemical, and biological evaluation factors, the ecological vulnerability to climate change were evaluated at each river in the Nakdong river basin. First, runoff, sediment rate, and low flow discharge changes according to AIB climate change scenario using the SWAT model were simulated. Also, for the assessment of chemical and biological factors, 48 points that water quality monitoring sites and ecological health measurement points are matched with each other was selected. The water quality data of BOD and T-P and the biological data of IBI and KSI in each point were reflected in the assessment. Also, the future rise in water temperature of the rivers in Nakdong river basin was predicted, and the impact of water temperature rise on the fish habitat was evaluated. The top 10 most vulnerable points was presented through a summary of each evaluation factor. This study has a contribution to river restoration or management plan according to the characteristics of each river.